The author of The Witcher books isn’t happy with what the success of the game has meant for his work.

With The Witcher 3, CD Projekt RED sold millions of copies worldwide, achieved vast critical acclaim, and even bagged a record number of Game of the Year awards. In the process, they also brought the Witcher brand, which originates from a series of dark high fantasy books written in Polish by famed author Andrzej Sapkowski, into the public eye.

You would think that Sapkowski would be happy about the success of the game, then, especially since a rising tide lifts all boats, and The Witcher 3‘s success can only mean good things for sales of his books. However, in a recent interview with Tygodnik POLITYKA (via The Wolf Hall), Sapkowski spoke out against the impact the game has had on his book sales.

“Seeing a picture from the game on the cover of my book, many fans assumed that the game was first,”Sapkowski said. “And respectable fans of sci-fi and fantasy hold such derivative books in contempt … I have to keep explaining to the fans that I wrote the book 12 years before the game was made and that the Sandworm is from the game, not the books. You couldn’t find a Sandworm in the books even if you tried.”

Sapkowski also has an issue with his books being sold with covers that use art from the games. His frustration caused him to lash out against game writers, saying that they “write game-related stuff exclusively for money. And surely they write in a sloppy manner, half-heartedly.”

That said, he did want to note that he had nothing against the game itself- rather, his problems were with the effects it was having on how his work was perceived.

“The issues that I have thanks to the games are not at all caused by the game itself,” he clarified. “I am not envious of the game’s undeniable success, I’m far from it. … There is but one original Witcher. That one which belongs to me. And nothing will take it away from me.”